According to American Society for Aesthetic Plastic Surgery (ASAPS) statistics, liposuction is one of the most popular plastic surgery procedures performed in the world. Approximately 456,000 procedures were carried out in the year 2005 in the U.S. alone and the numbers are growing.
Although traditional suction-assisted lipoplasty (SAL) is the most widely used technique, several new technologies have emerged for the lipoplasty procedure. These growing numbers of lipoplasty techniques have come to be known by acronyms such as SAL, PAL, UAL, E-UAL, VAL and so on. A brief glossary and overview of these liposuction techniques are discussed below.
Suction-Assisted Lipoplasty (SAL):
Suction-assisted lipoplasty is a traditional method during which fat is removed by inserting a hollow tube (cannula) with radial holes near the blunt tip through one or more small incisions near the area to be suctioned. The cannula is connected by tubing to a vacuum pressure unit, sucking the adjacent tissue into the holes and tearing it off by the reciprocating motion performed by the surgeon. The tumescent technique is the prior infusion of saline solution with minute amounts of anesthetic and vasoconstriction drugs.
Power-assisted lipoplasty (PAL) is a variant of SAL using a powered reciprocating cannula which reduces surgeon efforts. Both procedures are tedious, have considerable complications and are non-discriminating as to what is being removed.
Ultrasound-Assisted Lipoplasty (UAL)
Ultrasound-assisted lipoplasty adds the emulsifying property of high intensity ultrasound (mainly cavitation and heating) by setting up a standing wave in the specialized cannulae typically in the 25-30 kHz range. UAL equipment normally also includes equipment for infiltration of tumescent fluid both prior to the procedure and during the emulsification and aspiration as irrigation. This enhances the emulsifying cavitation effect and reduces the inherent heating. The technology is similar to what is used in industrial ultrasound drilling and phacoemulsification.
Vaser-Assisted lipoplasty (VAL) is a variant of UAL using pulsed wave (PW) rather than continuous wave (CW) ultrasound, which has the potential for separating the cavitation and heating mechanisms.
SAL, UAL and their variations remove fat non-uniformly as tunnels in a fan-like geometry from the incision(s) often resulting in a non-uniform skin surface in spite of the fact that the patient is required to wear compression garment(s) for some weeks. The patient recovery time is long and the procedure beyond the typical risk of the often-used general anesthesia can lead to serious complications.
External UAL
External UAL (E-UAL), which uses external ultrasound that may emulsify fat cells within the body, is still in the earliest stages of scientific evaluation. E-UAL typically consists of “softening” adipose tissue by externally applying high intensity ultrasound and using standard lipoplasty cannulae to remove the “softened” fat. The current technology has its historical roots to therapeutic ultrasound, hence has a frequency in the 1 to 3.5 MHz range and similar transducer shapes. The prior art literature does not disclose intensity levels or focusing.
Currently, there are two types of E-UAL systems. The major differences between the two systems are the use of one transducer versus two transducers, and variations in the technique of fat removal. One system uses suction to remove the liquefied fat. The other method follows the external ultrasound treatment with massage and the application of compression foam and garments. These procedures do appear to have advantages over invasive liposuction with very few complications reported to date, however it has not been accepted as an efficacious process.
High Intensity Focused Ultrasound (HIFU)
High intensity focused ultrasound is designed as a tissue ablation device mainly to treat cancer with ultrasound induced hyperthermia, but would also have the ability to assist in E-UAL. The technology typically is combined with ultrasound diagnostic imaging.
It has been shown that under the right conditions, high intensity ultrasound has fat discriminating properties, which mean that blood vessels, nerve endings and connective tissue are left intact while fat cells are destroyed.
Recognizing the demand for liposuction, as well as the potential of having serious complications from each of the above techniques, there is a significant opportunity for a safe and effective, less expensive and a user-friendly device that would provide benefits both to the surgeons and patients.